FIG. 1 depicts a schematic diagram of a portion of a typical wireless telecommunications system in the prior art, which system provides wireless telecommunications service to a number of wireless terminals that are situated within a geographic region. The heart of a typical wireless telecommunications system is the Wireless Switching Center ("WSC"), which may also known as a Mobile Switching Center ("MSC") or Mobile Telephone Switching Office ("MTSO"). Typically the Wireless Switching Center is connected to a plurality of base stations that are dispersed throughout the geographic area serviced by the system and to the local and long-distance networks. The Wireless Switching Center is responsible for, among other things, establishing and maintaining calls between wireless terminals and between a wireless terminal and a wireline terminal, which is connected to the system via the local and/or long-distance networks.
The geographic area serviced by a wireless telecommunications system is partitioned into a number of spatially distinct areas called "cells." As depicted in FIG. 1, each cell is schematically represented by a hexagon; in practice, however, each cell usually has an irregular shape that depends on the topology of the terrain serviced by the system. Typically, each cell contains a base station, which comprises the radios and antennas that the base station uses to communicate with the wireless terminals in that cell and also comprises the transmission equipment that the base station uses to communicate with the Wireless Switching Center.
For example, when wireless terminal 101-1 desires to communicate with wireless terminal 101-2, wireless terminal 101-1 transmits the desired information to base station 103-1, which relays the information to Wireless Switching Center 120. Upon receipt of the information, and with the knowledge that it is intended for wireless terminal 101-2, Wireless Switching Center 120 then returns the information back to base station 103-1, which relays the information, via radio, to wireless terminal 101-2.
When wireless terminal 101-1, wireless terminal 101-2 and base station 103-1 use Code Division Multiple Access ("CDMA") radio technology, it is paramount that each wireless terminal control the power with which it radiates its signal. Otherwise, a wireless terminal that radiates with too much power could cause a cacophony and swamp out the signals radiated by the other wireless terminals. Because it is so important that the radiated power of each CDMA wireless terminal be controlled, base station 103-1 continually provides commands to each wireless terminal directing the wireless terminal to increase or decrease the level with which it radiates. Furthermore, IS-95A Section 6.5 entitled "Malfunction Detection" states:
To ensure that a mobile station transmits a spread spectrum signal which does not adversely affect system capacity, the mobile station shall respond to the Lock Until Power Cycled Order and Maintenance Required Order from the base station as specified in 6.6.2.4, 6.6.3.2 through 6.6.3.7, and 6.6.4.3 through 6.6.4.5. It is the responsibility of the base station to detect a mobile station transmission malfunction and to send the appropriate message.
In other words, each base station in the wireless telecommunications system is responsible for monitoring each mobile station (i.e., a wireless terminal) to ensure that the wireless terminal behaves in a manner that does not adversely affect the number of calls that the wireless telecommunications system is capable of handling. When the base station does detect that a wireless terminal is behaving in a manner that adversely affects the number of calls that the wireless telecommunications system is capable of handling, then the base station can transmit a violation message to the wireless terminal that instructs the wireless terminal to cease the offensive behavior. The violation message can direct the wireless terminal to stop radiating any signal until the wireless terminal is re-booted, or the violation message can direct the wireless terminal to stop radiating until the wireless terminal has been examined and repaired by a technician. The standard further requires that a wireless terminal must comply with the violation message from the base station to be compliant with IS-95A.
Although the IS-95A CDMA standard requires malfunction detection, the standard does not provide guidance on how to detect a malfunction or specifically what set of circumstances even constitute a "malfunction." It is, however, generally known in the prior art that a rogue CDMA wireless terminal that radiates too much power can adversely affect the number of calls that the wireless telecommunications system is capable of handling, and, as a result, elaborate techniques have been developed and are well-known in the prior art for regulating the power with which a CDMA wireless terminal radiates. But it is one matter to know how to monitor and regulate the radiated power of an appropriately behaved wireless terminal and it is quite another matter to know how to monitor a wireless terminal and to discriminate between an appropriately behaved wireless terminal that is merely radiating too much power and an inappropriately behaved wireless terminal that is "malfunctioning" and should be sent a violation message.
Therefore, the need exists for a technique that discriminates between an appropriately behaved CDMA wireless terminal and an inappropriately behaved or "malfunctioning" CDMA wireless terminal.